I think you will be very disappointed with those cheaper abrasive wheel machines. Poor edges, no way to accurately true the wheels, or replace them, etc.
We do culinary knives, and others, in my sharpening business. All those draw-through abrasive wheel machines are junk. When I tooled up my business,I started with the most expensive abrasive wheel machine(Fredrich Dick)and gave up on it completely in a short while. I use a 1 x 30 belt sander with 600-800 grit to establish a two-angle edge(see John Juranich's book, The Razor Edge Book of Sharpening.) Then I hone on a paper wheel with pumice, available from ABS, Woodcraft Supply, etc. That is not an inexpensive system, but costs less than a Tormek(which I also use and will do knives wonderfully.)
Or, take the easy way, and buy a Spyderco Triangle Sharpmaker. I recommend it to customers and friends who just want to do a good job on a few edges at home. About $60 on the net, including a dvd, it's pretty foolproof. Versatile, offering the two-angle edge, and two grits on the sticks, it is not just another crock stick sharpener.
Tom Baldwin
Edge Wise, LLC